new yobk



Patented Nov. 6, 1923.

UNITED STATES PATENT orFIcE.

JOHN M. DONOHUE, OF ROCHESTER, NEW YORK,.ASSIGNOR TO EASTMAN KODAK CO1V"- PANY, OF ROCHESTER, NEW YORK, A CORTEORATION OF NEW YORK.

CELLULOSE-ETHER OMPOSITION.,

No Drawing.

To all whom it may concern.

Be it known that I, JOHN M. DoNoHUn,

a citizen of the United States of America,

residing at Rochester, in the county of Mon 5 roe and State of New York, have invented certain new and useful Improvements in Cellulose-Ether Compositions, of which the following is a full, clear, and exact specification.

This invention relates to solvents for making strong'solutions of cellulose ether and also relates to the cellulose ether compositions produced by the aid of such solvents. One object of my invention is to provide a solvent which will dissolve such large proportions of cellulose ethers that thick or viscous flowable solutions may be obtained for use in plastic and film making arts.

Another object of my invention is to provide a cellulose ether solution which may be manufactured into strong, flexible, transparent films on the machines and by the methods now in use. Other objects will hereinafter appear.

In U. S. PatentNo. 1,188,376, Lilienfeld, June 20, 1916, there are disclosed a series of alkyl ethers of cellulose. Certain of these are practically insoluble in water, and my invention relates, but is not limited, tothe ethers having that property. While cellulose ethers form thin solutions in the lower monohydroxy aliphatic alcohols or in epichlorhydrin, it has been found that such single solvents by themselves do not dissolve a sufiicient proportion of the ethers to make a desirably thick fiowable composition or dope, such as may be used in the manufacture of photographic film base by customary methods or in the other plastic arts.

I have discovered that an adequately strong and useful solvent may be prepared by mixing epichlorhydrin with one or more of the lower monohydroxy aliphatic alcohols. In other words, I have discovered that mixtures of these ingredients have a greater solvent action on cellulose ethers than similar weights of such ingredients when employed by themselves. By lower monohydroxy aliphatic alcohols, I mean those 50 having less than six carbon atoms.

While the ingredients may be mixed in widely varying proportions it is noted, by way of example, that a particularly useful with the aliphatic alcohol,

Application filed February 24, 1923. Serial No. 621,086.

composition can be prepared by mixing equal parts by weight of epichlorhydrin say methyl alcohol. In the preferred form of my invention, I dissolve 1 part by weight of the cellulose ether, say water-insoluble ethyl cellulose, in from 5 to 7 parts by weight of the solvent mixture. The ingredients by themselves are not sufliciently powerful to make properly fiowable solutions of this strength. Of course, the proportion of mixed solvent or the proportion of the volatile ingredients may be increased to adapt the composition to the lacquering art,

as will be understood by skilled persons.

Other substances which impart additional suppleness, or incombustibility, or other qualities, to the film may also be added to the'dope, such, for instance, as triphenyl or tricresyl phosphate, monochlornaphthalene, camphor, etc. The ingredients are of the ordinary commercial type and sufficiently purified for the process of film manufacture, so as to give a dope yielding films having the proper relative freedom from color. The viscousfiowable dope above described can be used in connection with the usual film-form ing apparatus without the necessity of ex pensive alterations in the latter.

In the formation of a film by the evaporation oft-he volatile ingredients from the hereinabove described compositions, a considerable amount of epichlorhydrin remains behind, because of its relatively low volatility. It imparts useful plastifying and other properties to the film, which is normally flexible and transparent. Since the ratio of the weight of epichlorhydrin to the weight of the cellulose ether can be made much greater by the use of my mixed solvent instead of using epichlorhydrin alone as a solvent, it follows that a correspondingly greater proportion of the epichlorhydrin will be present in the finished film than is present when cellulose ethers are dissolved in epichlorhydrin alone.

Having thus described my invention, what I claim as new and desire to secure by Let ters Patent is:

1. A composition of matter comprising cellulose ether dissolved in a mixture of epichlorhydrin and a lower monohydroxy aliphatic alcohol.

2. A composition of matter comprising cellulose ether dissolved in a mixture of epichloi'hydrin and methyl alcohol.

3. A fiowable composition comprising 1 part of cellulose ether dissolved in from 5 to 7 parts by weight of a mixture of epichlorhydrin and a lower monohydroxy aliphatic. alcohol. I

4. A composition of matter comprising cellulose ether dissolved in a mixture of substantially equal parts by Weight of epich1orhydrin and a lower monohydroxy aliphatic alcohol.

A 5. A composition of matter comprising 2 parts by Weight of Water-insoluble ethyl cellulose, 7 parts of epichlorhydrin and 7 parts of methyl alcohol.

6. As an article of manufacture, a deposited, flexible, transparent film comprising cellulose ether and. epichlorhydrin, the proportion of e'pichlorhydrin in said film being greater than the maximum proportion de'positable in a. transparent film "from a solu-- tion of said cellulose ether in epichlorhydrin alone.

Signed at Rochester, few York, this 16th day of February, 1923.

J OHN M. DONOHUE. 

